Deleting or nulling parameters via term table

Is there a way to delete, null or clear a parameter field via the term table? I want to clear the field if there is something there already.  Doing a "Delete Parameter" from the parameter editor seems rather crude, inefficient and prone to error or neglect. "*" doesn't change it. Empty cells are not allowed in the term table and spaces don't work either (not Null). I want to use it with a "if exists" type of query and if there is anything there, it exists.